Investigation on hydrogen production using multicomponent aluminum alloys at mild conditions and its mechanism

A series of Al alloys with low melting point metals Ga, In, Sn as alloy elements were fabricated using mechanical alloying method. The phase compositions and morphologies of different Al alloys were characterized by XRD and SEM techniques. The reaction of the Al alloys with water for hydrogen evolving at mild conditions (at room temperature in neutral water) was studied. The results showed that there were no hydrogen yields for binary Al–Ga, Al–In, Al–Sn and the ternary Al–Ga–Sn alloys. The hydrogen yields were observed for Al–Ga–In and Al–In–Sn ternary alloys. The Al–In–Sn alloys showed an even faster hydrogen generation rate and higher yields than Al–Ga–In alloys. Based on the ternary Al–Ga–In and Al–In–Sn system, the hydrogen production property of quaternary Al–Ga–In–Sn was greatly improved. The hydrogen conversion efficiency of the optimized Al–3%Ga–3%In–5%Sn alloy was nearly 100% in tap water. The highest hydrogen generation rate reached 1560 mL/g min in distilled water or deionized water. It was suggested that both the embrittlement of Al by liquid Ga–In–Sn eutectic and the active points formed by intermetallic compounds In3Sn and InSn4 may be attributed to the high activity of Al–Ga–In–Sn alloys at room temperature.

► Al was activated using Ga, In, Sn for hydrogen generation with water.
► The activity of Al was related to the alloy elements, amount and composition.
► Al–3%Ga–3%In–5%Sn shows high reactivity at room temperature with tap water.
► Hydrogen conversion efficiency for activated Al–3%Ga–3%In–5%Sn alloy is nearly 100%.
► Highest hydrogen generation rate can reach 1560 mL/g min.